Essential oils are natural aromatic liquids found in the roots, stem, bark, seeds, flowers, and other parts of plants. Technically, essential oils are fat soluble, non-water-based phytochemicals that include volatile organic compounds. The chemistry of any particular essential oil can be very complex and may consist of hundreds of different and unique chemical compounds. These oils give plants their distinctive smells, provide protection against disease, and assist in pollination. In their pure form, essential oils are translucent with colors ranging from clear to pink to blue. At different times throughout history, essential oils have also been used for medical purposes in which these oils have been inhaled, topically applied, or ingested.
The process of extracting essential oils from plant material often involves precise temperature and pressure control. In other words, extracting essential oil is a delicate procedure and the quality/extent of essential oil extraction from plant material is sensitive to and dependent on temperature and/or pressure parameters.